Averbeck N B, Borghouts C, Hamann A, Specke V, Osiewacz H D
Molekulare Entwicklungsbiologie und Biotechnologie, Johann Wolfgang Goethe-Universität, Botanisches Institut, Frankfurt am Main, Germany.
Mol Gen Genet. 2001 Jan;264(5):604-12. doi: 10.1007/s004380000346.
The lifespan of the ascomycete Podospora anserina was previously demonstrated to be significantly increased in a copper-uptake mutant, suggesting that copper is a potential stressor involved in degenerative processes. In order to determine whether changes in copper stress occur in the cells during normal aging of cultures, we cloned and characterized a gene coding for a component of the molecular machinery involved in the control of copper homeostasis. This gene, PaMt1, is a single-copy gene that encodes a metallothionein of 26 amino acids. The coding sequence of PaMt1 is interrupted by a single intron. The deduced amino acid sequence shows a high degree of sequence identity to metallothioneins of the filamentous ascomycete Neurospora crassa and the basidiomycete Agaricus bisporus, and to the N-terminal portion of mammalian metallothioneins. Levels of PaMt1 transcript increase in response to elevated amounts of copper in the growth medium and during aging of wild-type cultures. In contrast, in the long-lived mutant grisea, transcript levels first increase but then decrease again. The ability of wild-type cultures to respond to exogenous copper stress via the induction of PaMt1 transcription is not affected as they grow older.
先前已证明，在铜摄取突变体中，子囊菌柄孢壳霉的寿命显著延长，这表明铜是参与退化过程的潜在应激源。为了确定在培养物正常老化过程中细胞内是否发生铜应激变化，我们克隆并鉴定了一个编码参与铜稳态控制的分子机制组分的基因。这个基因，即PaMt1，是一个单拷贝基因，编码一种由26个氨基酸组成的金属硫蛋白。PaMt1的编码序列被一个内含子打断。推导的氨基酸序列与丝状子囊菌粗糙脉孢菌和担子菌双孢蘑菇的金属硫蛋白以及哺乳动物金属硫蛋白的N端部分具有高度的序列同一性。在生长培养基中铜含量升高时以及野生型培养物老化过程中，PaMt1转录本水平会升高。相比之下，在长寿突变体grisea中，转录本水平先升高但随后又下降。野生型培养物通过诱导PaMt1转录来对外源铜应激作出反应的能力在其生长过程中不受影响。
